DE127226C - - Google Patents

Description

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Dear ^ atentamtä bein 13th of October 1902 for nic & iig
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PATENT OFFICE

GREAT

for its manufacture.

Present invention

refers to one

Chromium-silicon steel and intended by special Composition of the same has a very high breaking strength with at the same time greater To achieve the toughness of the steel.

The purposes of the invention are achieved by because the steel has a carbon content which is below that usual for steel Limit of 0.0 pCt. is held, a content of silicon and chromium is given, which for chromium and silicon taken together from 1.5 to 2.5 pCt. fluctuates. the The best results are achieved when the chromium and silicon content are combined 2 to 2.5 pCt. is, while a lower content (down to 1.5 pCt. down) in those cases recommendable !! is when small amounts of nickel (up to 1.5 pCt.) are added to the steel should be.

Chromium-silicon-nickel steel grades are already known, but without the conditions under which steel of particularly great hardness and at the same time great toughness is obtained, and without even researching these conditions, since the intention was in the production of the previous chromium-silicon-nickel steel grades, the aim was not to have both hardness and toughness at the same time, but rather to be easy to harden in large quantities. Also, the purpose of adding silicon to the previous chromium-silicon-nickel steels was only indirectly to increase it slightly
little

manganese

and self-phosphorus, sulfur

the steel quality, insofar as it should guarantee a bubble-free Gufs, while with the The types of steel forming the subject of the invention are of fundamental importance owns; conversely, the addition of nickel, which is more fundamental with the older types of steel In the present case, it was important with regard to the desired steel properties more allowed than required.

It is important for the excellent properties of the steel grades forming the subject of the invention that they are not only low in carbon but also at the same time pure, in particular only
understandable too
and contain copper.

The steel grades containing silicon and chromium in the above-described mixing ratios the desired addition of these alloys is most expedient by appropriate addition of ferro-silicon and Ferro-chromium added to the melt, the percentage of these additions after Percentage of the silicon or chromium contained in the same directs.

The crucible melting process is used to produce the very best types of steel, because experience has shown that this is how the best results can be achieved. Of course can the steel grades, if not in the same holier, at least compared to the previous ones known types of steel in similarly excellent quality with the aid of flame furnaces,

vertern, Martinöfen '-or'deTgl. be produced. '"' ■ '' '■"

If the crucibles used in this crucible melting process have a high carbon content, z. B. in the form of graphite or coke powder, so is when melting through liver passage of carbon of the crucible in the Steel significantly affects its toughness. Even if the carbon content of the sealants is too high carbon passes into the steel. To counter this deficiency, the crucible insert is an addition of potassium bichiOmat optionally given in a mixture with chromic acid, which in connection with the silicon present during melting a extraordinarily beautiful effect in this way

on o

causes the excess carbon content of the ferrosilicon to oxidize, a depletion of carbon prevented from the crucible and any excess sulfur is removed as potassium sulfur, and finally some chromium is transferred into the steel, the latter being the whole of the hardness of the steel considerably increased, without, however, its great toughness being introduced even in the hardened state to do.

In contrast, an addition of KaliumbichiOmat without significant addition of silicon at the same time would have such an oxidizing effect on the liquid steel that blistered castings always take place, and the great advantage of it the unifying effect would be lost as a result. A simultaneous addition of considerable Quantities of silicon, on the other hand, remove this disadvantage and bring about the excellent effect of potassium dichromate to its full advantage.

Of the the

Invention forming

present

Subject of

Three types of steel have proven to be particularly excellent, which have the following composition:

variety C. Mn Si P. S. No. I. 0.48 O.Ct 2.uo 0.025 0.022 No. II 0.48 0.25 I, 00 0.025 0.022 No. Ill 0.48 0.25 0.50 0.025 0.022

Cu Ni Cr

Track ο to 0.50

Lane 1.00

Track ι, 00 ι, 00.

Claims (1)

Pate nt-An SPRüci-i E:
Low-manganese chromium-silicon steel, optionally also containing nickel, characterized in that with a carbon content of less than 0. t> pCt. the combined chromium and silicon content between 1.5 and 2.5 pCt. lies. Process for the production of the chromium-silicon steel according to claim 1 the crucible melting process, characterized by the addition of potassium dichromate. Supplementary sheet for patent specification 127226, class "8". By final decision of the Imperial Patent Office of October 13, 1902, the patent claim 1 is declared null and void .